Modify the configuration file /etc/apt/sources.list
Replace content
Ali mirror source
deb http://mirrors.aliyun.com/ubuntu/ vivid main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ vivid-security main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ vivid-updates main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ vivid-proposed main restricted universe multiverse deb http://mirrors.aliyun.com/ubuntu/ vivid-backports main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ vivid main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ vivid-security main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ vivid-updates main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ vivid-proposed main restricted universe multiverse deb-src http://mirrors.aliyun.com/ubuntu/ vivid-backports main restricted universe multiverse12345678910
Execution, normal is success
apt-get update
Installation tree, for viewing directory
apt-get install tree